Pyridoxine
Synonym :
Vitamin B6
Mechanism :
Vitamin B6 is a water-soluble B complex vitamin which is present in many foods as pyridoxine, pyridoxal and pyridoxamine. These forms of vitamin B6 are converted in vivo to pyridoxal phosphate and pyridoxamine phosphate, which are essential coenzymes in the metabolism of certain amino acids such as tryptophan, in carbohydrate and lipid metabolism, and in the synthesis of heme and GABA, an inhibitory neurotransmitter.
Indication :
- Pyridoxine responsive cystathionine deficiency
- Pyridoxine responsive cystathionine beta synthetase (CBS) deficiency (homocystinuria)
- Pyridoxine dependent seizures
- Penicillamine induced pyridoxine deficiency prophylaxis
- Isoniazid neuropathy
Contraindications :
Hypersensitivity to vitamin B6 or any component of a vitamin B6-containing pharmaceutical preparation.
Dosing :
RDA:
Upto 6 months: 0.1 mg/day
6-12 months; 0.3 mg/day
1-3 years: 0.5 mg/day
4-8 years: 0.6 mg/day
9-13 years; 1 mg/day
14-18 years (Male): 1.3 mg/day; (female) 1.2 mg/day
UL:
1-3 years: 30 mg/day
4-8 years: 40 mg/day
9-≤13 years: 60 mg/day
14-18 years: 80 mg/day
Metabolic indications:
50 mg/dose orally 1-2 times daily. Higher doses in partially responsive cases and for Wilson’s disease.
Pyridoxine dependent seizures:
Newborn: Oral: Try test dose of 50-100 mg 1-2 times daily for 2 days and if responsive, maintenance of 25-100 mg 2 times daily.
IV bolus: 50-100 mg as test dose; may give for 2 days and then change to oral.
Children: Oral: 20-50 mg PO 1-2 times daily upto 500 mg twice daily may be required.
IV bolus: 1 month-12 years: 25-100 mg as test dose for 2 days and then change to oral.
Adverse Effect :
Nausea, headache, paresthesia, somnolence and low serum folic acid concentrations have been reported. Peripheral neuropathy can occur following long-term administration of large doses.
Interaction :
Isoniazid: Causes pyridoxine deficiency.
Penicillamine: Causes pyridoxine deficiency.
Levodopa: Pyridoxine reduces the effect of levodopa but not if a dopa decarboxylase inhibitor is also given.
Oral contraceptives: Efficacy of pyridoxine is reduced.
Renal Dose :
Dose in Renal Impairment GFR (mL/min)
| 20-50 | Dose as in normal renal function |
| 10-20 | Dose as in normal renal function |
| <10 | Dose as in normal renal function |
Dose in Patients undergoing Renal Replacement Therapies
| CAPD | Unknown dialysability. Dose as in normal renal function |
| HD | Dialysed. Dose as in normal renal function |
| HDF/High flux | Dialysed. Dose as in normal renal function |
| CAV/VVHD | Unknown dialysability. Dose as in normal renal function |
Hepatic Dose :
No dosage adjustments are recommended.